kilgota@xxxxxxxxxxxxxxxxxxxxxx wrote:
Hans, Jean-Francois, and Kyle,
The proposed patches are not very long, so I will give each of them,
with my comments after each, to explain why I believe that these changes
are a good idea.
First, the patch to libv4lconvert is short and sweet:
contents of file mr97310av4l.patch follow
----------------------------------------------
--- mr97310a.c.old 2009-03-01 15:37:38.000000000 -0600
+++ mr97310a.c.new 2009-02-18 22:39:48.000000000 -0600
@@ -102,6 +102,9 @@ void v4lconvert_decode_mr97310a(const un
if (!decoder_initialized)
init_mr97310a_decoder();
+ /* remove the header */
+ inp += 12;
+
bitpos = 0;
/* main decoding loop */
----------------- here ends the v4lconvert patch ------------------
The reason I want to do this should be obvious. It is to preserve the
entire header of each frame over in the gspca driver, and to throw it
away over here. The SOF marker FF FF 00 FF 96 is also kept. The reason
why all of this should be kept is that it makes it possible to look at a
raw output and to know if it is exactly aligned or not. Furthermore, the
next byte after the 96 is a code for the compression algorithm used, and
the bytes after that in the header might be useful in the future for
better image processing. In other words, these headers contain
information which might be useful in the future and they should not be
jettisoned in the kernel module.
+1
Now, the kernel module ought to keep and send along the header and SOF
marker instead of throwing them away. This is the topic of the next
patch. It also has the virtue of simplifying and shortening the code in
the module at the same time, because one is not going through
contortions to skip over and throw away some data which ought to be kept
anyway.
+1
contents of file mr97310a.patch follow, for gspca/mr97310a.c
--------------------------------------------------------
--- mr97310a.c.old 2009-02-23 23:59:07.000000000 -0600
+++ mr97310a.c.new 2009-03-03 17:19:06.000000000 -0600
@@ -302,21 +302,9 @@ static void sd_pkt_scan(struct gspca_dev
data, n);
sd->header_read = 0;
gspca_frame_add(gspca_dev, FIRST_PACKET, frame, NULL, 0);
- len -= sof - data;
- data = sof;
- }
- if (sd->header_read < 7) {
- int needed;
-
- /* skip the rest of the header */
- needed = 7 - sd->header_read;
- if (len <= needed) {
- sd->header_read += len;
- return;
- }
- data += needed;
- len -= needed;
- sd->header_read = 7;
+ /* keep the header, including sof marker, for coming frame */
+ len -= n;
+ data = sof - sizeof pac_sof_marker;;
}
gspca_frame_add(gspca_dev, INTER_PACKET, frame, data, len);
@@ -337,6 +325,7 @@ static const struct sd_desc sd_desc = {
/* -- module initialisation -- */
static const __devinitdata struct usb_device_id device_table[] = {
{USB_DEVICE(0x08ca, 0x0111)},
+ {USB_DEVICE(0x093a, 0x010f)},
{}
};
MODULE_DEVICE_TABLE(usb, device_table);
------------ end of mr97310a.patch -------------------------
You will also notice that I have added a USB ID. As I have mentioned, I
have four cameras with this ID. The story with them is that two of them
will not work at all. The module will not initialize the camera. As far
as the other two of them are concerned, the module and the accompanying
change in libv4lconvert work very well. I have mentioned this
previously, and I did not get any comment about what is good to do. So
now I decided to submit the ID number in the patch.
Adding the USB-ID sounds like the right thing to do.
Regards,
Hans
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